TEMPLATE ASSISTED CYCLOTETRAMERISATIONS OF 1,2,5-THIADIAZOLE-3,4-DICARBONITRILE

1,2,5-Thiadiazole-3,4-dicarbonitrile 1 reacts with copper powder in a closed vessel and in an inert atmosphere to form the corresponding cop per porphyrazine 2a in fair fields. A similar reaction of 1 with magne sium powder gives about equal amounts of unchanged 1 and the triazine 3. Low yields of the magnesium porphyrazine 2b were obtained from reac tions of 1 with magnesium alcoholates in either 1-propanol or methanol . The required oxidation of sulfur from S(II) in 1 to S(IV) in the por phyrazines 2, and stereoelectronic requirements around the nitrile fun ctions of 1, might explain the reluctant formation of compounds 2.